There are various methods for characterizing loss factors and high-power characteristics in the piezoelectric materials. These are pseudo-static, admittance spectrum, and transient/burst mode methods. The admittance/impedance spectrum method is further classified into (1) constant voltage, (2) constant current, (3) constant vibration velocity, and (4) constant input energy methods. Piezoelectric resonance can be excited by either electrical or mechanical driving. In the k31 mode, as long as the surface is electroded, the sound velocity is v 11 E originated from s 11 E , while no-electrode, they are v 11 D and s 11 D . With the surface electrode, a short-circuit condition realizes the resonance and an open-circuit condition provides the antiresonance mode. In order to measure the D-constant parameters (s 11 D and its extensive elastic loss tan ϕ 11) directly, we need to use a non-electrode (NE) sample under mechanical driving methods.

First of all, the reader needs to have a suitable power supply to drive a piezoelectric actuator, which is a sort of prerequisite prior to reading further this chapter. The required power supply specifications should be better than the followings, in particular, in a multilayer (ML) actuator characterization: (a) Maximum Voltage: 200 (V), (b) Maximum Current: 10 (A), (c) Frequency Range: 0–500 (kHz), (d) Output Impedance: < 1 (Ω). You may use a conventional impedance analyzer, on which you should recognize that maximum voltage is only 30 V and the maximum current is less than 0.2 A with the output impedance 50 Ω. You should not believe the obtained admittance value for a large capacitance ML piezo-actuator measurement.